10 HP Seahorse questions

Commando1962 · Nov 20, 2011

Hi folks,

I recently traded a trailer for a 10 HP Johnson Seahorse. The motor does run, and the impeller shoots water like a charm. Unfortunately, the lower part of the OB was painted black, starting just below the power head. The only numbers that I was able to get from the serial plate are QDL 276551, or 4. The plate is in rough shape, and most of it is very faded. What year is this motor? It currently has J6C plugs, that will make it run hot, Correct? Should it have J4C. What should I gap these at.030? One last question; What is the mix ratio 24:1 or can I go leaner?

By the way, this is going on a 1962 14' Aerocraft Aluminum boat, which I have also stripped and repainted. Should look and work great!

Thanks,

Doug

HighTrim · Nov 20, 2011

Re: 10 HP Seahorse questions

I think there is a slight mistake in the model number you posted from the ID plate.

QD is correct, making it a 10hp, but you are missing the number after the QD, to ID the year for us. Once we determine the year correctly we can then answer the other questions.

A pic would help determine the year as well if the tag is completely illegible. What does it look like? Colours/is the cowl metal, etc....

kfa4303 · Nov 20, 2011

Re: 10 HP Seahorse questions

Hi Commndo. Welcome to iboats. We do need the number that follows the QD-XX to pin down the exact year, but all and all the 10 hp Johnson's were/are great little motors. I had a '61 that was great. About the only thing that goes wrong on them are the clutch dogs, which have a tendency to wear out over time. Here's a great link that can walk you through an entire tune up. While they changed the looks over the years the motors stayed practically unchanged for decades. The early-mid '50's models had a 2-line, pressure tank set-up, but they can be converted to a modern single line set up pretty easily. You can get virtually any part you may need (points and condensers, carb kit, impeller, etc...) right here at iboats too. Check out these links. Holler if you get stuck.

http://www.sschapterpsa.com/ramblings/johnson_QD.htm

rolmops · Nov 20, 2011

Re: 10 HP Seahorse questions

Is the engine block white,red or green,and does it have a fuel pump or does it have a pressure tank?

1946Zephyr · Nov 20, 2011

Re: 10 HP Seahorse questions

1949 - 55 Green
1956 - 58 Red
1959 - 63 White
Pressure tanks 1959 and prior Fuel pump single line tank, 1960 and later

There's a good refence for you if the model numbers don't make out.

samo_ott · Nov 20, 2011

Re: 10 HP Seahorse questions

Must be a QD12 or QD22 I would think as it seems to be missing a digit before the 2? A QD 22 is a '61.

And welcome to the forum

We love QD's here so post some pics and your questions

Commando1962 · Nov 21, 2011

Re: 10 HP Seahorse questions

Hi folks,

The motor has a fuel pump ( single line tank ), inside is white engine block, and the cowel is fibreglass . It is also missing the large outside idle knob. {how much would one of these be if it were available?} the centre knob is present and works. I have attached a pic of the motor. I think that this is a 63', but I could be wrong.

Thanks for all of your help folks,

1946Zephyr · Nov 21, 2011

Re: 10 HP Seahorse questions

Nice looking motor. That would be a '60 or later. Looks like someone did a decent job painting it. I believe all Johnson 10's were white from '59 - '63. Even the later 9.5's were white as well. They started using the greens again in the later half of the '60's.

samo_ott · Nov 22, 2011

Re: 10 HP Seahorse questions

It's a '59 or '60 with that ring on the top of the cowling. 24:1 mixture.

Here's the original flyer from 1960. Does it look like this one?

1946Zephyr · Nov 22, 2011

Re: 10 HP Seahorse questions

Good point samo. My '59 35 has that ring on top as well. According to what I found on Marine Engine website, that ring was on the covers into '61 as well. Since he stated that it does have a fuel pump, I'm betting it's a '60 - '61 model. The 35 and the Fat Fifty was really the motors that had fuel pumps in '59. Everything else was pretty much all pressure tank models.

Commando1962 · Nov 22, 2011

Re: 10 HP Seahorse questions

Hi folks,

My motor has some spots on the lower end whick were not painted porperly. They show a light green paint. The Word ,"Johnson" on the cowling does not have any other colours, or decals near it. Have a good look at the picture. The cover on the recoil is a light blue/green colkour. The front of the motor though, does look like the one on the brochure. . I'll tell ya, I stripped and repainted my 1979 7.5 merc( which has been upgraded to a 9.9 ), and I did a much better job than the previous owner of my Johnson. It'll be stripped an repainted as well

Commando1962 · Nov 22, 2011

Re: 10 HP Seahorse questions

Hey Chris,
Thanks for the Johnson link. Looks like it will be of great use.

Cheers,

Commando1962

bbstacker1 · Nov 23, 2011

Re: 10 HP Seahorse questions

I have a 61, it doesn't have the ring on top. If it has a fuel pump it should be a 60.

etracer68 · Nov 23, 2011

Re: 10 HP Seahorse questions

It may have the model number stamped into a core plug on one of the cylinders.

Commando1962 · Nov 25, 2011

Re: 10 HP Seahorse questions

Great link KFA4303. Thanks for the info. I will be attacking the minor tune up in a month or two. I've worked on loads of small engines, so this should be a minor issue. Right now, up here in Ontario Canada, we're tuning up for winter. I just completed a major overhaul of my Snowblower.... Engine, new drive chains, new tracks etc. She starts first pull, moves and steers great. Hopefully, when I need it to, she'll throw snow well.

Cheers,

Doug

Commando1962 · Nov 25, 2011

Re: 10 HP Seahorse questions

It does look very similar to this one. Maybe the paint job that was done to it altered it a bit Samo_ott. I am looking forward to getting htis out on the Bay of Quinte next spring. It's only a few hours drive from London.

samo_ott · Nov 26, 2011

Re: 10 HP Seahorse questions

I got my snowblower out today and fired it up also... But I also got out o the water in my '69 Evinrude 25 and bombed around for awhile

samo_ott · Nov 26, 2011

Re: 10 HP Seahorse questions

1946Zephyr said:
Good point samo. My '59 35 has that ring on top as well. According to what I found on Marine Engine website, that ring was on the covers into '61 as well. Since he stated that it does have a fuel pump, I'm betting it's a '60 - '61 model. The 35 and the Fat Fifty was really the motors that had fuel pumps in '59. Everything else was pretty much all pressure tank models.

Weird, I have the original flyer for the '61 and there's no ring on top... I wonder which one is wrong?

1946Zephyr · Nov 26, 2011

Re: 10 HP Seahorse questions

Yea, bbstacker1 just stated that his doesn't have the ring either. I wonder if they changed it nid-year and marine engine just displayed the first part of the year design. I just checked again and the motor cover they're showing is the same as the year prior. It could be a foul up.

Commando1962 · Nov 26, 2011

Re: 10 HP Seahorse questions

Hey Chris,

I just checked out the links that you posted. They will be extremely helpful. Thanks.

Doug

10 HP Seahorse questions

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